Make a very simple mechanical time delay?

  • Thread starter supak111
  • Start date
  • #1
43
1
Hey everyone, I need to make or design a simple mechanical time delay. This probably isn't easy since I can't find anything on the market thats small and cheap. Was thinking some wind up toy might work, haven't found the right one yet.

I was thinking maybe small box with a rod coming out of it (but open to ideas). If you push the rod all the way in it should take time for it to come out, maybe 2-5 minutes.

HOPING TO ACHEAVE:
~ Cheap under $3 but hopefully cheaper.
~ Small (hopefully smaller than a pack of cigarettes)
~ Needs to go in fast so no mechanical gearing on the way in.
~ Comes back out very slow 2-5 mins.
~ Needs to be able to push 1lb (maybe less not sure at the moment)

Does anyone have any ideas?

PS even a battery powered one would be ok if cheap. Haven't found anything similar already manufactured still.

.
 

Answers and Replies

  • #2
berkeman
Mentor
59,664
9,810
Hey everyone, I need to make or design a simple mechanical time delay. This probably isn't easy since I can't find anything on the market thats small and cheap. Was thinking some wind up toy might work, haven't found the right one yet.

I was thinking maybe small box with a rod coming out of it (but open to ideas). If you push the rod all the way in it should take time for it to come out, maybe 2-5 minutes.

HOPING TO ACHEAVE:
~ Cheap under $3 but hopefully cheaper.
~ Small (hopefully smaller than a pack of cigarettes)
~ Needs to go in fast so no mechanical gearing on the way in.
~ Comes back out very slow 2-5 mins.
~ Needs to be able to push 1lb (maybe less not sure at the moment)

Does anyone have any ideas?

PS even a battery powered one would be ok if cheap. Haven't found anything similar already manufactured still.

.
Can you sam more about the application? Is the 1lb load on low-friction rollers, or do you need 1lb-f applied through the whole movement of the arm? How far do you need to push the load?

You could start with a basic egg timer and adapt it maybe...

https://vignette4.wikia.nocookie.ne...g_timer.png/revision/latest?cb=20110402182025
latest?cb=20110402182025.png
 
  • #3
779
527
A dashpot?
 
  • #5
779
527
Interesting idea. Like with a weight to drive it?
Not necessarily, but not a bad thought, either. Dashpots come in a wide variety of types and ratings, for example, an air dashpot like those used in automotive carburetors may not provide 1 lb of force, but one based on hydraulics ought to. Outside of carbs, the only hands-on experience I have with them are old-fashioned pneumatic timer relays like the Allen-Bradley bulletin 700-NT, but (although the under $3 criteria may not be obtainable) I bet Google would turn up something to fit the bill.
 
  • #6
43
1
Thanks for your replies guys.

Dashpot sounds like a perfect idea especially since I wont have to modify it much. What makes the dashpot cool is most have adjustable timing like the dashpots on your house screen doors. Clock timer is a good one too if I can modify it to fit.

And the 1lb of push force might be over kill, I was just roughly estimating here. I'm gonna do some searching and see if I can find a dashpot thats pretty cheap and small hopefully adjustable timing too.
 
  • #7
Tom.G
Science Advisor
3,890
2,590
searching and see if I can find a dashpot thats pretty cheap and small
Not adjustable, but a hypodermic syringe meets the other qualifications. It does have a bit of static friction though.
 

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